Problem Solution Overview
We performed testing between the subject device and our 3150-MCM product.
Solution Brief
Our testing generated the following results:
- We were able to successfully communicate with the device. (see below for configuration parameters used during the testing)
- The product supports Modbus function codes 3 and 16.
The purpose of our testing is to assure a level of compatibility in the communications between the two products. Through this testing, we attempt to identify problem areas that may arise when implementing the interface in the field.
Configuration:
The product testing was performed with the following settings used for both devices.
Baud: 9600, 4800 and 2400
Parity: None, Even and Odd
Stop: 1 and 2
Mode: RTU Master Mode
Physical Connection : RS-485 (2 wire connection)
The Module Configuration used in our testing was as follows:
|
Address
|
0
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
|
N7:0
|
0
|
0
|
5
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
|
N7:10
|
1
|
1
|
5
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
|
N7:20
|
4
|
1
|
4
|
130
|
150
|
0
|
0
|
0
|
4
|
0
|
This configuration, in combination with the example ladder logic referenced below, generates the following memory map:
N10:0 to N10:129 - Slave Data
N10:130 to N10:149 - Slave Error Table (Contains revision level information also)
N10:150 to N10:199 - Master Error Table (Contains status of commands for diagnostics)
Command List:
The following command list shows some of the commands which were used to test the communications:
|
Address
|
0
Port
Number
|
1
Slave
Number
|
2
Function
Code
|
3
Source
Address
|
4
Count
|
5
Dest
Address
|
6
Read
Type
|
|
N7:50
|
1
|
1
|
3
|
0
|
28
|
0
|
0
|
|
N7:60
|
1
|
1
|
3
|
507
|
5
|
30
|
0
|
|
N7:70
|
1
|
1
|
6
|
200
|
1
|
30
|
0
|
|
N7:80
|
1
|
1
|
3
|
30
|
1
|
35
|
0
|
Our test command list performs the following functions.
- N7:50 Reads instrument flow information.
- N7:60 Reads instrument Modbus configuration.
- N7:70 Writes values from address 200 to insturment address 31.
- N7:80 Reads value from insturment address 31.
Cable Connection:
The physical connection which was used during testing was as follows:
|
MCM Module
|
|
Device
|
|
TXDRXD A (3100 - 14) - (3150 - 9)
|
--------------------------------------
|
Pin I/02
|
|
TXDRXD B (3100 - 25) - (3150 - 1)
|
-------------------------------
|
Pin I/01
|
|
RTS (3100 - 4) - (3150 - 7)
|
----------|
|
Jumper between RTS/CTS on
module must be installed
|
|
CTS (3100 - 5) - (3150 - 8)
|
----------|
|
|
GND
|
|
|
For ease of installation, termination on the ProSoft module was accomplished using our screw termination adaptor for the DB-25 plug. A similar screw termination plug is also available for the DB-9 required for the 3150-MCM.
The part number for these is:
1451-9F : DB-9 to RS-422/RS-485 Screw Terminals (for 3150-MCM)
1452-25M : DB-25 to RS-422/RS-485 Screw Terminals (for 3100-MCM)
|
